Sunken sprinkler heads often result from soil settling or the gradual accumulation of turf and thatch. When the head sits too low, the water stream hits the surrounding grass, severely reducing coverage and creating dry patches. The most efficient solution is to raise the head using a threaded riser extension. This simple technique avoids digging up the underground supply line, allowing you to quickly adjust the height and restore optimal water distribution.
Preparation and Necessary Supplies
Preparation begins by ensuring the entire irrigation system is depressurized. Locate and shut off the main water supply valve to the zone or the entire system. Accessing the sprinkler head connection requires only a small hand trowel or shovel to carefully clear the soil and turf surrounding the unit. The goal is to expose the threaded connection point at the base of the sprinkler head, not to dig down to the main lateral pipe.
The primary component is a polyethylene riser extension, often called a nipple riser, available in various lengths (e.g., 1, 2, or 3 inches). Measure the depth difference to select the correct length, aiming for the head to sit flush with the top of the grass. Thread sealing tape, commonly known as Teflon tape, is necessary to create a watertight seal at the connection points. Avoid oil-based pipe dope on plastic threads, as the petrochemicals can chemically attack the ABS plastic, causing it to weaken and crack.
The Riser Extension Method Step-by-Step
Start by carefully clearing the minimal amount of topsoil and grass until the connection threads are fully exposed. Gently unscrew the entire sprinkler head assembly counter-clockwise from the existing underground fitting, which may be a swing joint or a rigid nipple. Work slowly to avoid disturbing the surrounding soil and introducing debris into the main water line.
Once the head is removed, take the selected polyethylene riser extension. Wrap the male threads with thread sealing tape in a clockwise direction, applying three to five wraps for a secure seal. Wrapping the tape correctly ensures it does not unspool when threaded into the fitting. Hand-thread the riser extension into the exposed female fitting in the ground until it is snug.
The original sprinkler head must then be reattached to the top of the newly installed extension. For a reliable connection, the threads on the head’s inlet should also be wrapped with fresh Teflon tape before being screwed onto the riser. Tighten the head by hand, ensuring it is perfectly vertical to guarantee an even spray pattern and prevent water from pooling on one side.
The final step is to align the spray pattern with the area it is intended to water before final tightening. For spray heads, this means turning the entire body, while rotor heads require turning the nozzle turret. A slight over-tightening with channel locks or a similar tool may be necessary, but proceed with caution to avoid stripping the plastic threads and compromising the seal.
Post-Installation Testing and Adjustments
With the riser extension installed, turn the main water supply back on slowly to allow the system to repressurize without causing a sudden surge. Immediately inspect the base of the sprinkler head for any signs of water seepage or leaks, which indicate a thread seal failure.
Activate the zone to observe the spray pattern and confirm the raised height clears the turf completely. If the stream is still obstructed, a slightly longer riser may be needed. If the head is too high and presents a tripping hazard, replace it with a shorter riser.
Once the head is functioning correctly, carefully fill the hole with the soil and turf that was initially set aside. Lightly tamp the soil around the base to stabilize the head, ensuring its top surface is level with the surrounding lawn.